tempus fugit

Effects of marijuana use on impulsivity and hostility in daily life

2016-01-10

Emily B. Ansell

Holly B. Laws

Michael J. Roche

Rajita Sinha

Abstract

Background

Marijuana use is increasingly prevalent among young adults. While research has found adverse effects associated with marijuana use within experimentally controlled laboratory settings, it is unclear how recreational marijuana use affects day-to-day experiences in users. The present study sought to examine the effects of marijuana use on within-person changes in impulsivity and interpersonal hostility in daily life using smartphone administered assessments.

Methods

Forty-three participants with no substance dependence reported on their alcohol consumption, tobacco use, recreational marijuana use, impulsivity, and interpersonal hostility over the course of 14 days. Responses were analyzed using multilevel modeling.

Results

Marijuana use was associated with increased impulsivity on the same day and the following day relative to days when marijuana was not used, independent of alcohol use. Marijuana was also associated with increased hostile behaviors and perceptions of hostility in others on the same day when compared to days when marijuana was not used. These effects were independent of frequency of marijuana use or alcohol use. There were no significant effects of alcohol consumption on impulsivity or interpersonal hostility.

Conclusions

Marijuana use is associated with changes in impulse control and hostility in daily life. This may be one route by which deleterious effects of marijuana are observed for mental health and psychosocial functioning. Given the increasing prevalence of recreational marijuana use and the potential legalization in some states, further research on the potential consequences of marijuana use in young adults’ day-to-day life is warranted.

As nearly as can be determined from the abstract, this study involved forty-three subjects, who each kept a diary for fourteen days. The subjects were selected for an absence of a history of any substance dependence. They reported on their alcohol, tobacco, and marijuana use, and at the same time reported their feelings of impulsivity and interpersonal hostility concurrently. The limitations of this study are clear. There is no report as to whether the subjects kept notes in their diaries on other issues, which strikes me as odd. If one is keeping a diary of feelings and behaviors, one might well report on other things that are going on at the same time, and the fact that this is not mentioned limits the reach of the study. The most serious limitation of this study is the journal in which it is published: “Drug and Alcohol Dependence.”